Metal-fiber-latex-containing sheet materials

ABSTRACT

Sheet material consisting essentially of inorganic fibers, such as asbestos fibers, elastomer latex, such as neoprene latex, and finely divided metallic material, such as lead, the inorganic fibers being felted together and coated and adhered together by the elastomer latex and formed into a sheet, with the finely divided metallic material being maintained in the resulting formed sheet and affixed to the inorganic fibers by the elastomer latex, the sheet material preferably being coated on one surface with a water-impermeable material, such as bitumen or tar, or a water-resistant material, is useful as a pipe wrapping, such as pipe wrapping for gas transmission lines, as vibration dampening material or sound deadening material when affixed to a surface or as a radiation shielding material. The above-described sheet material is formed by preparing a watery admixture or furnish containing the inorganic fibers, latex and lead dispersed therein, effecting precipitation of the latex material onto the dispersed inorganic fibers and/or metallic material, followed by subjecting the resulting watery admixture to agitation and then forming a sheet therefrom by discharging or flowing the aqueous admixture onto a paper-making screen or sheet-forming roll or surface.

United States Patent 1 Tarlow 1 1 July 15, 1975 1METAL-FIBER-LATEX-CONTAINING SHEET MATERIALS [52] US. Cl. 428/40;428/220; 428/328; 428/354; 162/153; 162/155', 181/33 0;

[5 I] Int. Cl 1332b 19/02 8 Field of Search 161/167, 406, 158, 165,161/205, 217, 218, 182, D16. 4, 204,159,

P5624525 P/POZE'CT/VE COAT/1V6, e3. PAPE? PRESSURE 55/1/5/ 7/ 1; ADHES/5 l2 P/PEC/P/ 74 7' ED 51145701445)? ZATEX 2.5. A/EOP/PE/VF mrr PrimaryExaminer-George F. Lesmes Assistant Examiner-Alan T. McDonald Attorney,Agent, or FirmCooper, Dunham, Clark, Griffin & Moran [57] ABSTRACT Sheetmaterial consisting essentially of inorganic fibers, such as asbestosfibers, elastomer latex, such as neoprene latex, and finely dividedmetallic material, such as lead, the inorganic fibers being feltedtogether and coated and adhered together by the elastomer latex andformed into a sheet, with the finely divided metallic material beingmaintained in the resulting formed sheet and affixed to the inorganicfibers by the elastomer latex, the sheet material preferably beingcoated on one surface with a water-impermeable material, such as bitumenor tar, or a water-resistant material, is useful as a pipe wrapping,such as pipe wrapping for gas transmission lines, as vibration dampeningmaterial or sound deadening material when affixed to a surface or as aradiation shielding material. The above-described sheet material isformed by preparing a watery admixture or furnish containing theinorganic fibers, latex and lead dispersed therein, effectingprecipitation of the latex material onto the dispersed inorganic fibersand/or metallic material, followed by subjecting the resulting wateryadmixture to agitation and then forming a sheet therefrom by dischargingor flowing the aqueous admixture onto a paper-making screen orsheet-forming roll or surface.

8 Claims, 1 Drawing Figure IMPGA/V/C H55 e. 45555705 F/aE l4 METAlL/CMime/41 e. LEAD METAL-FlBER-LATEX-CONTAINING SHEET MATERIALS Thisinvention relates to sheet materials useful as vibration dampeningagents. sound deadening agents. gasketing material. special wrappingmaterial. such as pipe wrapping material. and radiation shieldingmaterial. In one particular embodiment this invention relates toflexible sheet material made up of high density metallic material. suchas lead. admixed with inorganic fibers. In another embodiment thisinvention relates to stiff of rigid sheet material made up of inorganicfibers. such as asbestos fibers. metallic material. such as finelydivided or powdered metal. and a thermoset resin which serves to impartstrength and rigidity or stiffness to the sheet material. In anotherembodiment this invention is directed to a method for the manufacture ofhigh density. inorganic fiber-containing sheet material. In stillanother embodiment this invention is directed to a method for themanufacature of limp and/or flexible sheet material characterized byhigh density and useful as radiation shielding or vibration dampening orsound deadending material.

Sheet materials useful as sound deadening or vibra tion dampeningmaterials have been prepared by incorporating or otherwise affixingfinely divided or powdered lead to a heavy cloth. such as canvas. Suchmaterials. howver. have not been completely satisfactory, particularlywhen exposed for a long period of time to the weather or when employedin a demanding environment. such as when employed as a pipe coating. inunderground gas transmission lines.

It has also been suggested to disperse or otherwise incorporate finelydivided metal. such as powdered lead. in a plastisol. such as apolyvinyl chloride plastisol. The resulting materials while satisfactoryfor many purposes are expensive and are not durable. Also. with respectto lead-loaded canvas sheets or polyvinyl plstisol leadloaded sheets. ithas been difficult and costly to manu* facture such materials sincespecialized equipment is necessary.

Accordingly. it is an object of this invention to provide an improvedsheet material useful as a vibration dampening or sound deadeningmaterial.

It is another object of this invention to provide a method. such as amethod employing paperforming techniques and/or equipment or machinery.for the manufacture of sheet material useful as a sound deadening orvibration dampening or radiation shielding material.

How these and other objects of this invention are achieved will becomeapparent in the light of the fore going disclosure and with reference tothe accompanying drawing which schematically illustrates in an enlargedcross-section one embodiment of sheet material prepared in accordancewith the practices of this invention.

lt has been discovered that sheet material consisting essentially ofinorganic fibers. such as asbestos fibers. and a latex. e.g. anelastomer latex. such as neoprene latex. and finely divided. preferablyhigh density mate rial. such metallic material. e.g. powdered lead. theinorganic fibers being substantially felted together and coated andadhered together by the elastomer latex and formed into a sheet with thefinely divided metallic material. preferably high density inorganic ormetallic material. being maintained in the resulting formed sheet andaffixed to the organic fibers by the precipitated elastomer latex. isuseful as a pipe wrapping or vibration dampening or sound deadeningmaterial.

Preferably. the sheet material is coated on one surface with awater-impermeable or water-resistant material. such as bitumen or tar.If desired. one side of the resulting formed sheet material may becoated with a pressure sensitive adhesive so that the resulting coatedsheet material can be readily affixed or attached to a surface. Ifdesired. there may also be incorporated in the resulting formed sheetmaterial a thermosetting agent which. upon curing. converts the sheetmaterial to a substantially rigid or stiff sheet. It is preferred.however. that the sheet material be flexible or limp and made up of highdensity material. suceh as finely divided or powdered lead. so that theresulting formed sheet material is especially useful as vibrationdampening or sound deadening material. particularly with respect to lowfrequency vibrations.

in the make-up of the sheet material in accordance with this inventionit is also preferred that the fiber content of the sheet material becomprised of substantially 1007: inorganic fibers. such as at leastabout 60% by weight inorganic fibers. Particularly useful as asbestosfibers. lf desired. however. there may be employed in place of ortogether with the asbestos fibers other inorganic fibers. such as carbonfibers. boron fibers. rock wool fibrous material. glass fibers. ceramicfibers. such as alumina fibers. and the like.

Further. as indicated hereinabove. or major or minor portion of thetotal fiber content of the sheet material may be comprised of organicfibrous material. such as paper pulp. paper. cloth and organic fibers.such as nylon. rayon. dacron. cotton. acetate. wool and the like. It ispreferred. as already mentioned. that when organic fibers are present inthe sheet material the organic fi' bers comprise less than 507r byweight fiber content based on the weight of the total fibers making upthe sheet material. and desirably less than about 25-30% by weight ofthe total weight of the resulting formed sheet material.

In the sheet material in accordance with this invention there is alsoincorporated therein a finely divided or powdered inorganic. preferablymetallic material. Particularly useful the finely divided or powderedmetallic material useful in the preparaton of the sheet material isfinely divided or powdered metal. Substantially may powdered metal isusefully incorporated in and employed in the manufacture of sheetmaterial in accordance with this invention. Suitably finely divided orpowdered metals include. iron. brass. stainless steel. Zinc. bronze.copper. beryllium. aluminum. silver. chromium. titanium. cobalt. nickel.tantalum. molybdenum and alloys or mixtures of one or more of the above.

Also useful as finely divided or powdered inorganic or metallic materialuseful in the sheet materials in ac cordance with this invention aresuch diverse materials as molybdenum disulfide. graphite. barytes orbarium sulfate. zinc oxide. zinc sulfide. tungsten carbide. leadsulfide. lead oxide and the like. Desirably. and preferably. when thesheet material is to be used as a vibration dampening or sound deadeningmaterial the finely divided or powdered inorganic material is a highdensity material. such a metal or inorganic material having a specificgravity greater than 5. preferably greater than 8. Particularly usefulas a high density finely material making up the sheet material is finelydivided or powdered lead or similar high density metals and compounds.i.e. specific gravity greater than about lU- l 2.

The elastomer latex employed as the binder for the associated fibrousmaterial and inorganic or metallic material making up the sheet materialof this invention may be substantially any commercially availableelastomer latex. Suitable elastomer latices would be abutadiene-acrylonitrile latex. such as Buna-N. neoprene latex. astyrene-butadiene latex. and acrylonitrile-butadienestyrene latex. apolybutadiene latex. a polyisoprene latex. natural rubber latex.polyvinylchloride latex and the like.

It is preferred in the practice of this invention to employ a latex.such as acrylonitrile-butadiene latex or neoprene latex ofpolyvinylchloride latex. which is weather and/or oil resistant and whichimparts suitable properties of flexibility and/or limpness and toughnessand stability to the sheet material as well as non-flammability.

The amount of latex making up the sheet material is a minor amount. suchas less than 20% by weight of the sheet material. usually in the range2-107: by weight of the sheet material. as opposed to the fiber contentwhich would be in the range not more elastomer about 5041071 by weightof the sheet material. usually in the range 5-3071. The finely dividedor curing inorganic or powdered material making up the sheet material ofthis invention usually comprises a substantial amount of the 53material. such as at least about lO/r by weight. Desirably. andpreferably. in accordance with this invention. the finely dividedpowdered inorganic or metal material makes up at least 50% by weight andmost desirably at least about 65-70% by weight on up to about 85-90% byweight of the sheet material. especially when the sheet material is tobe employed as a vibration dampening or sound deadening or radiationshielding material.

There may also be incorporated in the sheet material other materials.such as an antioxidant or heat and light stabilizers for the latexcomponent thereof. to improve its weathering properties and resistanceto oxidation. filling agents or color agents. such as inorganic materials. e.g. calcium carbonate. or dyes to impart a desirable color to thesheet material. Also. as indicated. par ticularly when a stiff or rigidsheet material is desired. there may also be incorporated in the sheetmaterial during its manufacture a cross-linking agent effective uponcuring to react or cross-link with the elastomer component. If desired.there may also be incorporated in the sheet material during manufacturea minor amount of a thermosetting resin effective upon curing orthcrmosetting to impart stiffness and/or rigidity to the resultingformed sheet material.

Further. as indicated hereinabove. the sheet material may be coated onone or both sides or surfaces with a pressure-sensitive adhesive orother suitable adhesive material so that the thus adhesive-coated sheetmaterial may be readily and easily attached to a surface. such as asupporting surface. by merely applying the adhesive coated surface ofthe sheet material thereto. When the sheet material is adhesive-coatedon both sides and after application or affixing one side of the sheetmatcrial to a supporting surface there may be applied to the other orremaining exposed adhesive-coated surface of the sheet material anothermaterial or structure so that the adhesive-coated sheet material isincorporated or installed between two structures or surfaces.

For handling purposes the pressure-sensitive or adhesive-coated surfaceof the sheet material has attached thereto a pcelable or readilyremovable coating or layer of material. such as a plastic film or waxedpaper. which would be stripped from the adhesive-coated surface justbefore the adhesive-coated surface of the sheet material is applied tothe structure or surface to which the sheet material is to be attachedor installed.

It has been mentioned hereinahove that the sheet material in accordancewith this invention in at least one embodiment is capable of beingmanufactured on conventional web or paper forming equipment. The factthat the sheet material of this invention which includes a substantialamount of finely divided or powdered inorganic material. such as finelydivided lead, can be satisfactorily manufactured on paper or othersheetforming equipment is surprising since it would appear that onewould expect that there would be a substantial loss or drainage away ofthe finely divided powdered metal with the water flowing or drainingthrough the paper or sheet-forming screen. 52

In the accompanying drawing there is illustrated in enlarged partialcross-section an example of one embodiment of the sheet material inaccordance with this invention. Specifically. there is illustrated.generally indicated by reference numeral 10. sheet material made up of alayer 15 composed of inorganic fibers 11. such as asbestos fibers. uponwhich is precipitated an elastomer latex 12. such as neoprene latex.Within layer [5 made up of inorganic fibers [0 and precipitated latex 12there is substantially uniformly dispersed therein finely dividedmetallic material 14, such powdered lead. having a particle size smallerthan 200 mesh. This flexible coherent layer 15 has applied on onesurface thereof layer or coating 16 of pressure-sensitive adhesivematerial. Desirably. for handling purposes. there is applied to layer orcoating 16 a protective or peelable top coating 17 of paper. plasticfilm or other material which readily strippable. such as by peeling.from pressure-sensitive adhesive layer 16. The other side or surface oflayer 15 has applied thereto coating or layer 18 of weather resistant orwater-proof material. such as bitumen or tar. if desired. coating orlayer 18 may be replaced or have applied thereto a decorative type film.such as a decorative plastic film, e.g. Mylar decorative film. or apolyvinyl chloride or polyolefin decorative film. e.g. polyethylene orpolypropylene.

In the use of the illustrative sheet material 10 as a sound deadening orvibration dampening material. with the lead content of the layer 15comprising about 80'/( thereof. strippable protective coating 17 wouldbe removed from a measured length of the sheet material 10 and theresulting exposed pressuresensitive layer 16 would be applied directlyto the surface to be protected or affected. such as to block radiation.to prevent or reduce sound transmission or vibra tion therethrough.There would be exposed surface 18 which could. as indicated hereinabove.be a waterresistant or weather-resistant coating. such as bitumen or taror. for decorative or indoor purposes a decorative plastic film.

In the manufacture of the sheet material of this in vcntion employingconventional paper or sheetforrning equipment. such as equipment usefulfor the manufacture of sheet asbestos. there is formed a wateryadmixture or furnish made up of the fibrous materials. such as asbestosfibers. and the elastomer latex. such as an acrylonitrile-butadienclatex, e.g. Buna-N latex, with the wetting r wetting down of the fibrousmaterial in the water, preferably with the aid of a wetting or dispersing agent, such as an anionic surfactant, such as Darvan, a sodiumsalt of polymerized alkyl naphthalene sulfonic acids or sodium salts ofpolymerized substi tuted benzoid alkyl sulfonic acids or aryl alkylsulfonic acids, eg Darvan No. 6 manufactured by R. T. Vanderbilt Co.,New York. NY. The finely divided metal lie or inorganic material is thenadded, such as finely divided powdered lead having a particle sizesmaller thatn 200 mesh. After agitating the resulting'liquid admixtureor furnish made up of asbestos fibers, elasto mer latex, lead anddispersing agent, precipitation of the latex onto the fibrous material,such as the asbestos fibers, and to some extent onto the finely dividedpowdered inorganic material takes place, usually within about minutes.Desirably, a trace amount of an aqueous calcium chloride solution, byweight CaClis added to effect complete precipitation and clarity in thewatery admixture.

The resulting watery admixture now containing the ellastomer latexsubstantially and completely precipitated onto the fibrous material isheated, such as to a temperature in the range l0()l50F., cg. about130F., and pumped or agitated for a short time, such as for not morethan a few minutes, e.g. about lO6() seconds. The resulting wateryadmixture or furnish is then flowed onto or discharged onto apaper-making come at least partly felted and adhered together by theelastomer coating. The elastomer latex coating also serves to entrap orentrain the finely divided or powdered inorganic or metallic material,such as finely di 5 vided lead, together with the fibrous material withthe result there is formed a substantially uniform and homogeneous sheetmaterial consisting essentially of the fibrous material, elastomer latexand the finely divided or powdered inorganic or metallic material issubstan- IO tially the same proportions or relative amounts as orginallyemployed in the makeup of the abovedescribed watery admixture After theformation of the sheet material on the screen or sheet-forming surfaceit is removed, desirably after water has been expressed therefrom, suchas by 5 material having a substantially reduced, less than about l% byweight, water content.

A number of sheet materials in accordance with this invention wereprepared generally in accordance with the above-described procedure. Theformulation,

screen or surface. 3 make-up, properties and procedure for the manufac-Upon discharge of the watery admixture to the pature of these sheetmaterials are set forth hereinbelow per-making screen or surface theasbestos fibers bein the accompanying tables.

TABLE NO. 1

FORMULATION l 2 3 4 s 7 8 Composition lbs lbs. lbs. lbs. lbs. lhs. lbs.lbs.

Bleached sulfite 'J 9 9 Asbestos fibers 11 2| "i ll 3U 3O 3O 3O 10% byWeight aqueous calcium chloride solu tion truce trace Lead. particlesize e Elli) mesh 5.1 5!.1)

Drainage-seconds 0.9 ().9

Pressure (tonsl l3 2H Caliper lthick ncssl inch 0.0385 0.0M?

lllZ

ll).2 i ll).2

2H4 llll H12 lHlbl 0.068

Tensile lbs. pull s9 53 4| 33 Tensile psi i475 i226 73 490 4 i TABLE NO.1 -Continued FORMULATION l 2 3 4 5 6 7 8 Composition lbs. lbsv lbs. lbs.lbs. lbs. lbs. lhs.

7% by weight rubber (total solids) 22.7 H 7.2 4.2 7.2 4.2

It b wei ht lea (tota solids) ll 55 72 X5 72 KS 72 72 TABLE NO. 2

9 10 ll 12 Furnish Grams Grams Grams Grams Asbestos fibers 40 40 40 4t)Polyvinylchloride latex (dry basis) l2 l2 Neoprene latex (dry basis] l2l2 Powdered lead I l20 I20 I20 Santo-white L2 l.-

Calcium chloride (10% solution) l0 ml. l0 ml. l5 ml. 15 ml.

Pulping time (seconds) l4 l4 l4 l4 Consistency ('7?) 3 3 3 3Precipitation Temp. F. 80 R0 80 80 Drainage Temp. F. I00 100 l0!) I00Caliper (inches) 0.0560 0.0584 0.0553 0.0562

Weight 6"X6 (grams) 90.88 974 I031: I023 Weight 500 ft.'-' (lbs) 400.23428.94 456.25 45052 Density (lbs.lcu.ft.) l7l.52 l76.27 198.0l 192.39

Tensile (lhs. pull) 32.5 44.5 57.25 61.75

Tensile (psi) 575 723 l l33 i199 Drainage (seconds) 0.85 0.95 2.4 L9

Wire Release Ex Ex Ex Ex Precipitation time (minutes) 23 IO 22 Leadsettling 0 U trace trace In the preparation of the sheet material inaccordance with this invention employing the formulations indicated inTables Nos. l and 2 and following the procedures described hereinabove.it was observed that no lead or only trace amounts of lead were found inthe drainage. All formulations had excellent wire release from thesheet-forming screen.

Sheet materials in accordance with the abovedescribed technique and madeup of neoprene as the elastomer latex and Buna-N as the elastomer latexand containing 7271 by weight powdered lead were very flexible and had adensity about ll 59 lbs./cu.ft. and weight 53 lbs/I00 ft. at 0.04l inchthickness.

The sheet materials prepared in accordance with the above formulationsand procedures or techniques have a wide utility and permit a wide rangeof formulation. For example, and particularly useful as vibrationdampening or radiation shielding. sheet materials consisting essentiallyof powdered lead, asbestos and elastomer latex are readily prepared.Such materials would resist acid and alkali attack. would tend not tobecome brittle on weathering. would resist cold flow and flow atelevated temperatures, would exhibit good flexibility for easyinstallation and. as indicated hereinabove, could readily be prepared invarious thicknesses. Because of the above-indicated physical propertiessheet materials prepared in accordance with this invention would beusefl as radiation shielding materials for use in connection with radarcooking equipment, x-ray equipment. instrument shielding. radioacativeclean rooms, television sets and pipe wraps. especially wraps for pipescontaining radioactive materials. These materials would also be usefulas noise deadening material. useful for sound insulation with respect towalls. roofs and doors. such as by being laminated to or fixed to doorsand walls or enclosures of rooms containing compressors, pumps.generators. engines. as well as for insulation in submarines to preventnoise leakage and for use in vibration dampening, e.g. in connectionwith natural gas transmission lines. particularly on lines in closeproximity to compressor stations. The materials of this invention wouldalso be useful as gasketing materials. The materials of this inventionwould also be readily useful as specialized roofing material and thelike. for use in connection with outdoor installations and the like.

As will be apparent to those skilled in the art in the light of theforegoing disclosure, many modifications. alterations and substitutionsare possible in the practice of this invention without departing fromthe spirit or scope thereof.

1 claim:

1. Sheet material consisting essentially of asbestos fibers, a polymerlatex selected from the group consisting of neoprene latex andacrylonitrile-butadiene latex and finely divided lead. said asbestosfibers being present in said sheet material in an amount in the rangeabout 5-30'71 by weight and being felted together and coated and adheredtogether by said polymer latex and formed into a sheet. said polymerlatex being present LII in said sheet material in an amount in the rangeabour Z-ZW/r by weight and said finely divided lead being maintained inthe resulting formed sheet material and affixed to said asbestos fibersby said polymer latex. said finely divided lead comprising at leastabout 50'7: by weight of said sheet material.

2. Sheet material in accordance with claim I wherein said finely dividedlead has a particle size smaller than 200 mesh.

3. Sheet material in accordance with claim I wherein said polymer latexis neoprene latex.

4. Sheet material in accordance with claim I wherein said polymer latexis a acrylonitrile-butadiene latex.

5. Sheet material in accordance with claim I wherein a coating of apressure-sensitive adhesive is applied to at least one surface or sideof said sheet material.

6. Sheet material in accordance with claim I wierein a coating ofpressure sensitive adhesive material is ap plied to both sides orsurfaces of said sheet material.

7. Sheet material in accordance with claim I wherein a coating ofpressure-sensitive adhesive material is applied to at least one side orsurface of said sheet material and a film or layer of protective.strippable or peelable material is applied on top of said coating ofpressure-sensitive adhesive material.

8. Sheet material in accordance with claim 1 wherein said sheet materialhas a thickness of about 0.01 to about 0.25 inch.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. I 3,895,143

DATED L July 15, 1975 INVENTOMS): Hilton J. TarlowHiscaflfiedmatamrammaminflwzmmw-memfimdpamntmdflwtsmdLeflmsPamm arehereby corrected as shown below:

Col. 1, line 11, "of", first occurrence, should read I-'-- line 22,"deadending" should read deadening line 37, "plstisol" should readplastisol Col. 2, line 14, succh" should read such line 23, "as" shouldread are line 29, "or" should read a line 45, "preparaton" should readpreparation line 47, "may" should read any line 51, after "zinc," inserttin,

Col. 3, line 15, "of" should read or line 24, delete "elastomer" andinsert than line 26, delete "curing" and insert powdered line 29, delete"53" and insert sheet Col. 4, line 21, "52" should be omitted line 39,after "which" insert is Col. 5, line 12, "thatn" should read than line23, "ellastomer" should read elastomer (continued) Page 1 UNITED STATESPATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO.3,895,143

DATED 1 July 15, 1975 INVENTOR(S) Hilton J. Tarlow It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Page 2 Col. 6, line 9, "is" should read in Col. 8, line 66, "usefl"should read useful Col. 10, line 1, "abour" should read about line 17,"wierein" should read wherein Signed and Scaled this twenty-fifth D a )1Of November I 9 75 [SEAL] A nest.

RUTH C. MASON Commissioner uj'latems and Trademarks

1. SHEET MATERIAL CONSISTING ESSENTIALLY OF ASBESTOS FIBERS, A POLYMERLATEX SELECTED FROM THE GROUP CONSISTING OF NEOPRENE LATEX ANDACRYLONITRILE-BUTADIENE LATEX AND FINELY DIVIDED LEAD, SAID ASBESTOSFIBERS BEING PRESENT IN SAID SHEET METERIAL IN AN AMOUNT IN THE RANGEABOUT 5-30% BY WEIGHT AND BEING FELTED TOGETHER AND COATED AN ADHEREDTOGETHER BY SAID POLYMER LATEX AND FORMED INTO A SHEET, SAID POLYMERLATEX BEINGG PRESENT IN SAID SHEET MATERIAL IN AN AMOUNT IN THE RANGEABOUT 2-20% BY WEIGHT AND SAID FINELY DIVIDED LEAD BEING MAINTAINED INTHE RESULTING FORMED SHEET MATERIAL AND AFFIXED TO SAID ASBESTOS FIBERSBY SAID POLYMER LATEX, SAID FINELY DIVIDED LEAD COMPRISING AT LEASTABOUT 50% BY WEIGHT OF SAID SHEET MATERIAL.
 2. Sheet material inaccordance with claim 1 wherein said finely divided lead has a particlesize smaller than 200 mesh.
 3. Sheet material in accordance with claim 1wherein said polymer latex is neoprene latex.
 4. Sheet material inaccordance with claim 1 wherein said polymer latex is aacrylonitrile-butadiene latex.
 5. Sheet material in accordance withclaim 1 wherein a coating of a pressure-sensitive adhesive is applied toat least one surface or side of said sheet material.
 6. Sheet materialin accordance with claim 1 wierein a coating of pressure sensitiveadhesive material is applied to both sides or surfaces of said sheetmaterial.
 7. Sheet material in accordance with claim 1 wherein a coatingof pressure-sensitive adhesive material is applied to at least one sideor surface of said sheet material and a film or layer of protective,strippable or peelable material is applied on top of said coating ofpressure-sensitive adhesive material.
 8. Sheet material in accordancewith claim 1 wherein said sheet material has a thickness of about 0.01to about 0.25 inch.